The present invention relates to an apparatus for the ventilation of liquid tanks in aircraft during hazardous pressure rises where a pipe line ventilating the tank terminating above the tank is provided in all positions of the aircraft.
From German Laid-Open Document No. 2,347,635 there is known a ventilating apparatus on a gear box where a ventilation pipe projects on the side into the center of the tank so that the end of the ventilation pipe at any position of the gearbox is above the lubricant level forming in the tank.
Based on the lubricant quantity required for adequate lubrication, the known apparatus assumes a tank volume which must be many times the tank volume required by the lubricant.
In the known case there results a lubricant tank of relatively large dimensions and a relatively large weight.
In view of the payload space requirement and the weight, use of such apparatus in aircraft is not desirable.
Furthermore, liquid tanks during ventilation in aircraft are exposed to much more extreme operating conditions than is the case with other machines, such as drilling presses, etc.
These conditions include maintenance of the tank inside pressure in spite of relatively large acceleration forces acting on the liquid tank, as may arise with sudden and relatively fast descending or ascending flight or with relatively fast rotation of an aircraft about its roll axis, with simultaneous allowance for the mass inertia of the liquid in the tank.
It is an object of the present invention to eliminate the shortcomings in the present state of the art and to provide an apparatus which will ensure optimum ventilation of the liquid tank in all flight attitudes with relatively low tank volume.
Another object of the present invention is to provide an arrangement of the foregoing character which is substantially simple in construction and may be economically fabricated.
A further object of the present invention is to provide an arrangement, as described, which may be readily maintained in service and which has a substantially long operating life.